wrote:
I may have talked about this idea before but it was inspired when I was
doing blister repairs on a boat and used a heat gun. The heat gun
literally drove water from the hull and it poured out of adjacent
blisters so...........Why waste time heating the glass when you really
want to heat the water and other polar molecules. Enclose the boat in
a cover of aluminized plastic and put a microwave generator inside.
The water and other polar molecules in the gel coat would be driven out
over a few days. Of course you'd have to keep the power level low
enough to not cause arcing near any metal fittings but that should be
easy. You might want to score the gelcoat to facilitate the
evaporation of the water.
Next, you drive thermo-setting resin into the gel coat under pressure
or even slowly setting ultra-low viscosity epoxy. Finally a sealer
coat. No BS gel coat peeling that fails 80 % of the time.


The vast majority of blisters affect only the gelcoat and do not lead
to delamination of the
hull. Most exotic blister repairs accomplish little or nothing to
extend the life or improve the strength of the hull, and some do
considerable damage. Best advice for those with cosmetic, gelcoat
blisters is to forget about them and enjoy the boat. It's appropriate
to check for any sign of delam during the periodic haulout, whether
there are cosmetic gelcoat blisters or not. It would be hard to imagine
that the cosmetic benefit of a microwave approach would outweigh the
potential damage to other portions of the boat.

chuck,
Do you not recommend popping the blisters, allowing the blisters to dry out
and applying an epoxy coat? That doesn't sound exotic, and I thought it
would be prudent for any boat that is kept in the water.


wrote in message
oups.com...

wrote:
I may have talked about this idea before but it was inspired when I was
doing blister repairs on a boat and used a heat gun. The heat gun
literally drove water from the hull and it poured out of adjacent
blisters so...........Why waste time heating the glass when you really
want to heat the water and other polar molecules. Enclose the boat in
a cover of aluminized plastic and put a microwave generator inside.
The water and other polar molecules in the gel coat would be driven out
over a few days. Of course you'd have to keep the power level low
enough to not cause arcing near any metal fittings but that should be
easy. You might want to score the gelcoat to facilitate the
evaporation of the water.
Next, you drive thermo-setting resin into the gel coat under pressure
or even slowly setting ultra-low viscosity epoxy. Finally a sealer
coat. No BS gel coat peeling that fails 80 % of the time.


The vast majority of blisters affect only the gelcoat and do not lead
to delamination of the
hull. Most exotic blister repairs accomplish little or nothing to
extend the life or improve the strength of the hull, and some do
considerable damage. Best advice for those with cosmetic, gelcoat
blisters is to forget about them and enjoy the boat. It's appropriate
to check for any sign of delam during the periodic haulout, whether
there are cosmetic gelcoat blisters or not. It would be hard to imagine
that the cosmetic benefit of a microwave approach would outweigh the
potential damage to other portions of the boat.

Reggie Smithers wrote:
chuck,
Do you not recommend popping the blisters, allowing the blisters to dry out
and applying an epoxy coat? That doesn't sound exotic, and I thought it
would be prudent for any boat that is kept in the water.


Such a "surface" treatment is about all the trouble the situation
really warrants.
And anybody who convinces a boater to stick a boat into a "drying tent"
and spend $1000's in lay days (or lay weeks) to cure blisters should be
ashamed.

One of our local yards does a very good job of blister repair. Their
process involves a peel job and then the application of a few layers of
vinylester laminate under a new barrier coat. They put a lifetime
warranty on the process, and in ten years they have had only one or two
boats back for a re-do. They are the local exception.

Most blister repairs fail. Some sooner than others. The good news is,
for the vast majority of blisters there is absolutely no reason beyond
cosmetics to deal with them at all. 99% of the time they are out of
sight below the waterline.

I had a batch of chine blisters that I dealt with two or three bottom
paint jobs ago. Just sanded them flat, let them dry for a few hours,
faired them out, and slapped on the bottom paint. Cost was less than
$100. I fully expect to see those same blisters back again some day
(but maybe not)........and if I do I'll spend another $100 to deal with
them. That's much better than spending $10,000 or $20,000 or maybe more
to deal with them and *still* having them reappear in the future.

Delamination, of course, is another and very serious problem.
Blistering does not "progress" to delam, although in very rare cases
blistering may be an indication of an underlying delam problem. Got
delam? You're going to have to deal with it whether you see blisters or
not. Got blisters without delam? No big deal. Taking a drastic course
to remove them would be like spending $20,000 to have a surgeon remove
a benign mole from your butt cheek- it isn't hurting a darn thing and
almost nobody will ever see it.

wrote in message
ups.com...

Reggie Smithers wrote:
chuck,
Do you not recommend popping the blisters, allowing the blisters to dry
out
and applying an epoxy coat? That doesn't sound exotic, and I thought it
would be prudent for any boat that is kept in the water.


Such a "surface" treatment is about all the trouble the situation
really warrants.
And anybody who convinces a boater to stick a boat into a "drying tent"
and spend $1000's in lay days (or lay weeks) to cure blisters should be
ashamed.

One of our local yards does a very good job of blister repair. Their
process involves a peel job and then the application of a few layers of
vinylester laminate under a new barrier coat. They put a lifetime
warranty on the process, and in ten years they have had only one or two
boats back for a re-do. They are the local exception.

Most blister repairs fail. Some sooner than others. The good news is,
for the vast majority of blisters there is absolutely no reason beyond
cosmetics to deal with them at all. 99% of the time they are out of
sight below the waterline.

I had a batch of chine blisters that I dealt with two or three bottom
paint jobs ago. Just sanded them flat, let them dry for a few hours,
faired them out, and slapped on the bottom paint. Cost was less than
$100. I fully expect to see those same blisters back again some day
(but maybe not)........and if I do I'll spend another $100 to deal with
them. That's much better than spending $10,000 or $20,000 or maybe more
to deal with them and *still* having them reappear in the future.

Delamination, of course, is another and very serious problem.
Blistering does not "progress" to delam, although in very rare cases
blistering may be an indication of an underlying delam problem. Got
delam? You're going to have to deal with it whether you see blisters or
not. Got blisters without delam? No big deal. Taking a drastic course
to remove them would be like spending $20,000 to have a surgeon remove
a benign mole from your butt cheek- it isn't hurting a darn thing and
almost nobody will ever see it.


The microwave concept is really a pretty neat idea at first look. An
improvement might be to just treat the blisters and surrounding area. No
need for a screen room. Just a directional microwave. They do it for
termites, just monitor the temperature, to avoid superheated areas, that
would explode. use the mw to heat the water up to a simmer. Might even be
a good way to check for osmosis. Moisture meter is not going to really
check for water behind an area of good gel coat. It can not sense the
water, and if it is a density checker, extra resin or glass is going to
change the readings. mw the hull and check for hotter spots. Like Chucks
blisters. Use the mw to accelerate the drying. Would be cheaper than
vacuum drying. A lot less time. Or use it in combination with mw and
vacuum drying.

Don't sand thru the gelcoat if you don't have to, Chuck. Fiberglass isn't
waterproof without it. Patch the ground out blisters with Marine Tex or
other waterproofing filler.
JIMinFL
wrote in message
ups.com...


I had a batch of chine blisters that I dealt with two or three bottom
paint jobs ago. Just sanded them flat, let them dry for a few hours,
faired them out, and slapped on the bottom paint. Cost was less than
$100. I fully expect to see those same blisters back again some day
(but maybe not)........and if I do I'll spend another $100 to deal with
them. That's much better than spending $10,000 or $20,000 or maybe more
to deal with them and *still* having them reappear in the future.

I'll never do this cuz I have waaaaaaay too many other weird projects.
It came out of a scheme of mine to measure the fluid level in oil wells
using microwaves.
I have done a lot of looking into blister repair and even have done
some of it. What I find is that blister repair is mostly a scam that
fails about 80% of the time. As others have pointed out, blisters are
really only a cosmetic problem. I have NEVER heard of osmotic blisters
causing hull failure on a boat made from woven fiberglass. I HAVE
heard of severe problems in hulls made from short strand mats. If
anybody has ever heard of a hull failure or accident resulting from
Osmotic Blisters, i'd like to hear about it.

Thanks

David

JIMinFL wrote:
Don't sand thru the gelcoat if you don't have to, Chuck. Fiberglass isn't
waterproof without it. Patch the ground out blisters with Marine Tex or
other waterproofing filler.
JIMinFL

I don't know how you would fix a blister without removing the deformed
gelcoat.

Gelcoat ( essentially a layer of tinted resin) is somewhat porous. You
may be thinking of a barrier coat, not the gelcoat. When the term
"osmotic blister" is applied, the osmosis is the passage of water
through the gelcoat, not through the laminate. Plastic doesn't absorb
water, so if there are no voids in an FRP hull it isn't ever going to
become "waterlogged".

When I refer to "fairing", that's the same process you describe above
with the filler.

Happy New Year

My thinking is backward from yours, Chuck. I think of the gel coat as the
layer that is supposed to be waterproof. The laminate may or may not be
waterproof depending on how well the layers are saturated with resin. I'm
sure if you scrape the gelcoat off something like a BayRay or other mass
produced boat, you will have a leak.
JIMinFL
wrote in message
oups.com...

JIMinFL wrote:
Don't sand thru the gelcoat if you don't have to, Chuck. Fiberglass isn't
waterproof without it. Patch the ground out blisters with Marine Tex or
other waterproofing filler.
JIMinFL

I don't know how you would fix a blister without removing the deformed
gelcoat.

Gelcoat ( essentially a layer of tinted resin) is somewhat porous. You
may be thinking of a barrier coat, not the gelcoat. When the term
"osmotic blister" is applied, the osmosis is the passage of water
through the gelcoat, not through the laminate. Plastic doesn't absorb
water, so if there are no voids in an FRP hull it isn't ever going to
become "waterlogged".

When I refer to "fairing", that's the same process you describe above
with the filler.

Happy New Year

JIMinFL wrote:
My thinking is backward from yours, Chuck. I think of the gel coat as the
layer that is supposed to be waterproof. The laminate may or may not be
waterproof depending on how well the layers are saturated with resin. I'm
sure if you scrape the gelcoat off something like a BayRay or other mass
produced boat, you will have a leak.
JIMinFL

I don't always agree with David Pascoe on some issues, but I think he
has written one of the most informative and easily understood essays on
blisters and how they affect a boat.
If you check out the illustrations and explanation at this link, you
might amend your opinion about gelcoat preventing leaks in a fiberglass
hull


http://www.yachtsurvey.com/BuyingBlisterBoat.htm

On Mon, 2 Jan 2006 22:28:17 -0500, " JimH" jimh_osudad@yahooDOTcom wrote:


wrote in message
roups.com...
I may have talked about this idea before.........

Here is an idea. Why not address questions presented to you in other
threads you started before starting yet another new thread?


Jim, are you just looking for a fight? My gosh, you posed the question,

"For the rich????????"

Was that really supposed to be more than rhetorical?

You're trying with Harry, now you're trying with dhohara. Why not knock it off?

Jeeeesh!

--
John H.

"Divide each difficulty into as many parts as is feasible and necessary to resolve it."
Rene Descartes